1. Field of the Invention
The present invention relates to a shift knob structure mounted to a shift shaft of a vehicle transmission.
2. Description of the Related Art
Various shift knob structures mounted on upper part of the shift shaft (shift lever) have been proposed in the past. Patent document 1 discloses a shift knob mounting structure in which a pair of left and right locking grooves are formed on the outer circumference of the shift lever, and a substantially Ω-shaped pin member is mounted to a pair of left and right pin fitting grooves provided in the lower cylindrical portion of the shift knob body. In the shift knob mounting structure disclosed in patent document 1, the top of the shift lever is inserted into the insertion hole of the shift knob body. When the pin member reaches the pair of locking grooves formed in the shift lever, a pair of curved locking portions of the pin member are set and locked in the locking grooves of the shift lever. A cover member is mounted to the lower cylindrical portion of the shift knob body from below. The interior side surface of the cover member comes into contact with the pin member from outside of the pin member and presses the pin member so as not to be expanded radially outward.
[patent document 1] JP2007-22536
The shift knob mounting structure disclosed in patent document 1 requires the job of pinching the pin member with fingers and removing the pin member from the pin fitting grooves in order to detach the shift knob body from the shift lever for maintenance, etc. Because the pin member is elastic, the job of removing the pin members from the pin fitting grooves needs to be carried out with discretion so as not to flip the pin member. As such, the related-art structure leaves much to be desired in terms of workability.
The pin member is pinched with fingers to detach the shift knob body from the shift lever. Therefore, a space to pinch the pin member needs to be created by moving the cover member downward and away from the lower cylindrical portion of the shift knob body by a distance sufficient to accommodate two fingers. This creates an additional problem in that the side surface of the shift lever between the position thereon aligned with the lower end of the cover occurring when the cover member is mounted on the shift knob body and the position occurring when the cover member is moved downward in order to remove the pin member is not suitable to form a design in consideration of the possibility that the cover member sliding along the side surface of the shift lever may damage the side surface.